Remote attestation of modular devices with multiple cryptoprocessors

ABSTRACT

A methodology for requesting at least one signed security measurement from at least one module is provided. The methodology includes receiving the at least one signed security measurement from the at least one module; validating the at least one signed security measurement; generating a signed dossier including all validated signed security measurements in a secure enclave, the signed dossier being used by an external network device for remote attestation of the device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority to, U.S.application Ser. No. 16/782,235 entitled REMOTE ATTESTATION OF MODULARDEVICES WITH MULTIPLE CRYPTOPROCESSORS, filed Feb. 5, 2020, which isrelated to and claims priority under 35 U.S.C. § 119(e) to U.S. patentapplications No. 62/830,060, filed Apr. 5, 2019 and No. 62/829,869,filed Apr. 5, 2019, the entire contents of which are incorporated hereinby reference for all purposes.

TECHNICAL FIELD

The present disclosure generally relates to the field of computernetworking, and more particularly to assessing reliability andtrustworthiness of devices operating within a network.

BACKGROUND

Modern networking devices are increasingly modular, wherein line cards,route processors, or other modules can be inserted or removed from asupervisor device. On top of their modularity, these modules often comeequipped with their own cryptoprocessors, which require securityvalidation above and beyond validation of the supervisor device'scryptoprocessors. However, current methods do not provide a means tovalidate all cryptoprocessors in a device that persists across itslifetime independent of which modules are present.

BRIEF DESCRIPTION OF THE FIGURES

To provide a more complete understanding of the present disclosure andfeatures and advantages thereof, reference is made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIGS. 1 through 3 illustrate example networking environments inaccordance with some examples;

FIG. 4 illustrates an example of a controller orchestratedattestation-based routing, in accordance with some examples;

FIG. 5 illustrates an example system in accordance with some aspects ofthe present technology;

FIG. 6 illustrates an example method in accordance with some aspects ofthe present technology;

FIG. 7 illustrates an example network device in accordance with someexamples; and

FIG. 8 illustrates an example computing device architecture inaccordance with some examples.

DETAILED DESCRIPTION

Various embodiments of the disclosure are discussed in detail below.While specific implementations are discussed, it should be understoodthat this is done for illustration purposes only. A person skilled inthe relevant art will recognize that other components and configurationsmay be used without parting from the spirit and scope of the disclosure.Thus, the following description and drawings are illustrative and arenot to be construed as limiting. Numerous specific details are describedto provide a thorough understanding of the disclosure. However, incertain instances, well-known or conventional details are not describedin order to avoid obscuring the description. References to one or anembodiment in the present disclosure can be references to the sameembodiment or any embodiment; and, such references mean at least one ofthe embodiments.

Reference to “one embodiment” or “an embodiment” means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the disclosure. Theappearances of the phrase “in one embodiment” in various places in thespecification are not necessarily all referring to the same embodiment,nor are separate or alternative embodiments mutually exclusive of otherembodiments. Moreover, various features are described which may beexhibited by some embodiments and not by others.

The terms used in this specification generally have their ordinarymeanings in the art, within the context of the disclosure, and in thespecific context where each term is used. Alternative language andsynonyms may be used for any one or more of the terms discussed herein,and no special significance should be placed upon whether or not a termis elaborated or discussed herein. In some cases, synonyms for certainterms are provided. A recital of one or more synonyms does not excludethe use of other synonyms. The use of examples anywhere in thisspecification including examples of any terms discussed herein isillustrative only, and is not intended to further limit the scope andmeaning of the disclosure or of any example term. Likewise, thedisclosure is not limited to various embodiments given in thisspecification.

Without intent to limit the scope of the disclosure, examples ofinstruments, apparatus, methods and their related results according tothe embodiments of the present disclosure are given below. Note thattitles or subtitles may be used in the examples for convenience of areader, which in no way should limit the scope of the disclosure. Unlessotherwise defined, technical and scientific terms used herein have themeaning as commonly understood by one of ordinary skill in the art towhich this disclosure pertains. In the case of conflict, the presentdocument, including definitions will control.

Additional features and advantages of the disclosure will be set forthin the description which follows, and in part will be obvious from thedescription, or can be learned by practice of the herein disclosedprinciples. The features and advantages of the disclosure can berealized and obtained by means of the instruments and combinationsparticularly pointed out in the appended claims. These and otherfeatures of the disclosure will become more fully apparent from thefollowing description and appended claims, or can be learned by thepractice of the principles set forth herein.

OVERVIEW

The disclosed technology presents a solution for verification of modularnetworking devices with multiple cryptoprocessors. The solution detailsmethods, systems, and non-transitory computer-readable media forcreating a signed attestation bundle (a single signed envelope) for suchsupervising (modular) devices that can be indicative of signed andverified status of all constituent devices residing within thesupervising device. Such single signed envelopes may be created using anattestation key that is not tied to a specific hardware on which thesupervising device is deployed, allowing it to persist across hardwareiterations of the modular device.

A method can include requesting at least one signed security measurementfrom at least one module with a corresponding cryptoprocessor, the atleast one module existing within a device; receiving the at least onesigned security measurement from the at least one module with thecorresponding cryptoprocessor; validating the at least one signedsecurity measurement; generating a signed dossier including allvalidated signed security measurements in a secure enclave, the signeddossier being used by an external network device for remote attestationof the device.

A non-transitory computer-readable medium can include instructionsstored therein which, when executed by at least one processor, cause theat least one processor to request a plurality of signed securitymeasurements from a plurality of modules with correspondingcryptoprocessors, the plurality of modules existing within a device;receive the plurality of signed security measurements from the pluralityof modules with corresponding cryptoprocessors; validate the pluralityof signed security measurement; generate a signed dossier including allvalidated signed security measurements in a secure enclave, the signeddossier being used by an external network device for remote attestationof the device.

A system can include a computing device, the computing device comprisingat least one module with a corresponding cryptoprocessor; a secureenclave; and a supervisor cryptoprocessor configured to request at leastone signed security measurement from the at least one module with thecorresponding cryptoprocessor, receive the at least one signed securitymeasurement from the at least one module with the correspondingcryptoprocessor, validate the at least one signed security measurement,generate a sign dossier including all validated signed securitymeasurements in the secure enclave, the signed dossier being used by anexternal network device for remote attestation of the device.

EXAMPLE EMBODIMENTS

The disclosed technology addresses the need in the art for verificationof modular networking devices with multiple cryptoprocessors. Modernnetworking devices often hold modules, such as line cards or routers,which contain their own cryptoprocessors in addition to thecryptoprocessors held in the supervising device. This disclosureprovides non-limiting examples for creating a signed attestation bundle(a single signed envelope) for such supervising (modular) devices thatcan be indicative of signed and verified status of all constituentdevices residing within the supervising device. Such single signedenvelope may be created using an attestation key that is not tied to aspecific hardware on which the supervising device is deployed. Prior todescribing such examples embodiments, several example configurations inwhich the above concepts can be deployed and utilized, will be describedfirst.

The disclosure now turns to an initial discussion of example conceptsand technologies for providing verifiable proof of integrity of networknodes traversed by packets.

A computer network can include different nodes (e.g., network devices,client devices, sensors, and any other computing devices) interconnectedby communication links and segments for sending data between end nodes.Many types of networks are available, including, for example, local areanetworks (LANs), wide area networks (WANs), software-defined networks(SDNs), wireless networks, core networks, cloud networks, the Internet,etc. When data traffic is transmitted through one or more networks, thedata traffic typically traverses a number of nodes that route thetraffic from a source node to a destination node.

While having numerous nodes can increase network connectivity andperformance, it also increases security risks as each node that a packettraverses introduces a risk of unauthorized data access andmanipulation. For example, when a packet traverses a node, there is asecurity risk that is introduced which can result from the node beingpotentially compromised (e.g., hacked, manipulated, captured, etc.). Asa result, compliance, security, and audit procedures can be implementedto verify that network users, devices, entities and their associatednetwork traffic comply with specific business and/or security policies.

When sensitive information is transmitted through nodes in a network,such as in battlefield, banking settings, and healthcare settings, suchtraffic should be sent through uncompromised nodes to prevent access to,leakage of, or tampering with the data and sensitive information carriedby that traffic. If an attacker gains access to a device via someexploit, previous protection and encryption approaches for networkinterfaces are generally ineffective at mitigating or addressing suchunauthorized access and resulting damage.

Proving that network traffic complies with specific policies can involveproving in a secure way that the traffic has traversed a well-definedset of network nodes (e.g., firewalls, switches, routers, etc.) and thatsuch network nodes have not been modified or compromised. This can helpensure that the network nodes have performed their expected or intendedactions (e.g., packet processing, security or policy complianceverification, routing, etc.) on the packet and that the packet hastraversed the network nodes.

Some security approaches can aim at removing any implied trust in thenetwork used for connecting applications hosted on devices to cloud orenterprise hosted services. Moreover, some security approaches can beimplemented to verify the trustworthiness (e.g., the integrity,identity, state, etc.) of the network and/or nodes traversed by packets.In some cases, certain verification checks can be implemented tovalidate or verify that traffic has traversed a specific set of nodesand that such nodes are trusted and uncompromised. In some examples,certain Proof-of-Transit (POT), Trusted Platform Module (TPM),attestation, or proof of integrity approaches can be implemented toverify or validate the trustworthiness of a node in a network.

POT can enable a network user or entity to verify whether traffictraversed a defined set of network nodes. Attestation, as furtherdescribed below, can also be used to verify the integrity of a node. Insome cases, the approaches herein can integrate both to offer a secureapproach that allows network users or entities to verify that traffichas traversed a defined set of nodes and that such nodes have not beencompromised.

In some cases, TPM can be implemented to collect and report the identityof hardware and software components in a platform to establish trust forthat platform. A TPM used in a computing system can report on thehardware and software of the system in a manner that allows verificationof expected behavior associated with that system and, from such expectedbehavior, establishment of trust. The TPM can be a system componentcontaining state that is separate from the host system on which the TPMreports identity and/or other information. TPMs can be implemented onphysical resources (indirectly or directly) of the host system. In someexamples, a TPM component can have a processor and memory such as RAM,ROM and/or flash memory. In other implementations of a TPM, a hostprocessor can run TPM code while the processor is in a particularexecution mode. Parts of system memory can be partitioned by hardware toensure that memory used by the TPM is not accessible by the hostprocessor unless the host processor is in the particular execution mode.

In some cases, trusted computing (TC) implementations, such as TPM, canrely on Roots of Trust. Roots of Trust can be system elements thatshould be trustworthy because misbehavior by such system elements maynot be detectable. A set of roots can provide a minimum functionalitythat can sufficiently describe characteristics that affect a platform'strustworthiness. In some cases, determining if a Root of Trust isbehaving properly may not be possible; however, it may be possible todetermine how roots are implemented. For example, certificates canprovide assurances that the root has been implemented in a way thatrenders it trustworthy.

To illustrate, a certificate may identify the manufacturer and evaluatedassurance level (EAL) of a TPM. Such certification can provide a levelof confidence in the Roots of Trust used in the TPM. Moreover, acertificate from a platform manufacturer may provide assurance that theTPM was properly installed on a system that is compliant with specificrequirements so the Root of Trust provided by the platform may betrusted. Some implementations can rely on three Roots of Trust in atrusted platform, including Root of Trust for Measurement (RTM), Root ofTrust for Storage (RTS), and Root of Trust for Reporting (RTR).

The RTM can send integrity information, such as integrity measurements,to the RTS. Generally, the RTM can be a processor controlled by a CoreRoot of Trust for Measurement (CRTM). The CRTM is the first set ofinstructions executed when a new chain of trust is established. When asystem is reset, the processor (e.g., RTM) can execute the CRTM, whichcan then send values that indicate its identity to the RTS. Thus, insome cases, the starting point for a chain of trust can be establishedin this manner.

As previously noted, the TPM memory can be shielded from access by anentity other than the TPM. Since the TPM can be trusted to preventunauthorized access to its memory, the TPM can act as an RTS. Moreover,the RTR can report on the contents of the RTS. An RTR report can be adigitally signed digest of the contents of one or more values in a TPM.

Attestation is another example trusted computing approach that can beused to verify the integrity of a node. Attestation can be applied to anode, such as a router or switch, to review logs from connected devices,such as Layer 1 (L1) or Layer (L2) connected devices and maintain theselogs in trusted storage. These logs can be protected by embedding aprivate key into every trust anchor produced for a hardware device andpublishing the device's public key as a certificate to adjacent devices.This peering device can then push log updates from trusted storageperiodically and/or on some log entry event. Reviewing any providedsigned logs can provide an understanding of the current trustable stateof a peer device. Moreover, by looking back at the set of transactionswhich have occurred since boot time, a determination can be maderegarding the trustworthiness of the information which that peer deviceis asserting.

In some examples, metadata elements containing security measurements orevidence, can be used to provide verifiable evidence of devicetrustworthiness (e.g., integrity, state, etc.). The metadata elementscan include applicable data for verifying trustworthiness of a deviceand be provided through an applicable technique for verifying devicetrustworthiness. For example, the metadata elements can be provided aspart of a canary stamp associated with the device. A canary stamp canindicate or otherwise include a signed measurement associated with adevice for verifying trustworthiness of the device. In turn, suchmeasurements can be referred to as canary stamps because each signedmeasurement is like a stamp proving its authenticity, and like a canaryin a coal mine that indicates an early sign of trouble. Such verifiableevidence can be appended or included in packets transmitted by nodes ona network. The metadata elements can thus be used to evaluate thetrustworthiness of a node(s) and react accordingly. For example, adevice or entity can review metadata element associated with a node todetermine that the node should not be trusted and adjust a networkpolicy to mitigate possible damage.

In some implementations, dedicated cryptoprocessors, such as a processorin TPM platform, can take measurements to attest to the trustworthiness(e.g., identity, integrity, etc.) of a node and its environment (e.g.,software, hardware, operating system, running binaries, firmware, etc.).These measurements include evidence that the node is in a safe state. Insome cases, these measurements can be provided through canary stamps, aspreviously described. However, a receiver of such evidence should beable to certify that the evidence is fresh, as the evidence can becomestale thereby potentially reducing its effectiveness in reflecting thecurrent trustworthiness of a node. For example, without ensuringfreshness of such evidence, an attacker has an opening to injectpreviously recorded measurements and asserting what is replayed as beingcurrent.

Some approaches can detect the replaying of old evidence via a “nonce”.A nonce is an arbitrary number that can be used to introduce randomness.In some instances, a nonce can be used just once in a cryptographiccommunication. Further, a nonce can be passed into a TPM and/orincorporated into a canary stamp/metadata. In some cases, a resultprovided by the TPM can include a signature based on the nonce. Sincethe nonce can be grounded in a transactional challenge/responseinteraction model, in some cases the nonce may be less effective withunidirectional communications originating from an attesting device. Forexample, a nonce may less effective with an asynchronous push,multicast, or broadcast message.

However, there are numerous use cases where a platform assessing whetherits peers are trustworthy is advantageous. Being able to perform aunidirectional attestation using an asynchronous push, multicast, orbroadcast message in conjunction with trusted binaries opens manypossibilities for platforms to assess whether their peers aretrustworthy. Detection of invalid attestations can trigger alarms orevents, reduction of network access from a suspect device, or can becomea part of Admission Control (e.g., IEEE 802.1X). Some platforms can beconfigured to support the unidirectional attestation mechanism.

Other freshness approaches can be based on trusted computingcapabilities, such as TPM. For example, a token can be generated whichallows external entities to validate freshness of asserted data based onthe state of internal counters within the TPM. This token can be used todetect replay attacks, and provide attestation for asynchronous push,multicast, and broadcast messages.

Various of the foregoing approaches can be combined with TPM-integratedcapabilities aimed at verifying that valid compute components, such asbinary processes, are running on a node. These capabilities can include,for example, Trusted Execution Environments (TEE) which provide runtimemalware protections, Authenticated Code Modules (ACM) which ensure thatonly digitally-signed code modules can be loaded into a processor, andthe like. These technologies can validate that a processor is runningknown software with a valid chain of binary signatures.

In some cases, metadata elements, e.g. canary stamps, and tokens can becreated by extracting current counters (e.g., clock, reset, restart)from a node's TPM, and incorporating such counters and security measurestaken from the node into a packet. In some examples, the currentcounters and/or security measures can be hashed with information withinan external TPM. The metadata elements and tokens can thereby provide anon-spoofable token or metadata element, which can bind continuouslyincrementing counters on an attestee with a known external state. Anyresetting of the TPM counters is visible in any subsequent TPM queries,and any restarting of a platform is also exposed in subsequent TPMqueries. Within these bounds of reset and restart, the TPM's time tickscounter continuously increments. Therefore, any push of attestee TPMinformation which includes these counters can be determined to haveoccurred subsequent to any previously-received measurement. Also, if thereset and restart counters have not changed, the incremental time sinceany previous measurement can also be known.

In some cases, a large amount of information that should be trusted bynetwork peers may not be contained within the TPM's ProgramConfiguration Registers (PCR). As a result, indirect methods ofvalidating that a node has not been compromised can be applied.

The receipt of the metadata elements, e.g. canary stamps, and/or tokenscan mean that a receiver should have the option of verifying theinformation. In many cases, such verification can be performed withoutthe need of supplementary evidence being sent with the canary stamp.Moreover, in non-controller based or centralized implementations, theverification steps do not have to occur at the receiver.

In some integrity verification implementations, a controller or devicecan implement an integrity verification application. The integrityverification application can be designed to recognize change events andevaluate known good values, which allow evaluation of a boot-integritystamp and a running process binary signature stamp based on, forexample, TPM counters, timestamps, nonces, and/or time tokens. On anydiscrepancy, a controller or centralized device can isolate acompromised node from its network peers by shutting down the interfacesof the node.

In some examples, the metadata elements, e.g. canary stamps, and/orverifications for integrity can be implemented, such as a measured-bootstamp (e.g., SHA1 hash over PCRs 0-7), a verified-boot stamp (e.g.,which can verify that only recognized binaries were executed whenbooting), a process-stamp (e.g., root-of-trust validated through aprocess which is asserting a particular protocol or protocols), afile-system stamp (e.g., all files within a vendor determined set ofdirectories), a log-integrity stamp (e.g., used to augment existingintegrity analytics and forensics), a configuration stamp (e.g., Stateof the current device configuration), etc. Some implementations canachieve all or some of these stamps, depending on the implementation.Moreover, in some implementations, all or some of these stamps can beimplemented or achieved using a single or multiple stamps.

As previously explained, TPM provides methods for collecting andreporting the identity of hardware and software components in a platformto establish trust for that platform. TPM functionality can be embeddedin a variety of devices including mobile phones, personal computers,network nodes (e.g., switches, routers, firewalls, servers, networkappliances, etc.), and/or any other computing devices. Further,attestation can describe how the TPM can be used as a hardware root oftrust and offer proof of integrity of a node. Such integrity can includehardware integrity, software integrity (e.g., micro loader, firmware,boot loader, kernel, operating system, binaries, files, etc.), andruntime integrity.

In some cases, TPM and attestation can be implemented as describedherein to provide proof of integrity and proof of transit throughuncompromised nodes. In some examples, metadata elements and tokenscontaining or reflecting security measures are used as previouslymentioned to validate the integrity of a node and perform continuousevaluation of node integrity. Thus, the metadata elements and tokensdescribed herein can be used to provide proof of transit throughuncompromised nodes.

In some examples, the metadata elements and tokens can be added asadditional metadata to packets that traverse a network where proof oftransit via uncompromised nodes is desired. Various strategies can beimplemented for transporting the metadata elements and tokens in apacket. In some cases, the metadata elements and tokens can be carriedwithin an In-Situ (or in-band) Operations, Administration and Management(IOAM) data field.

In some implementations, the metadata elements and tokens can be carriedwith IOAM trace data. For example, a canary stamp can be carried as partof an IOAM data field in a variety of encapsulation protocols such as,for example and without limitation, IPv4, IPv6, NSH (Network ServiceHeader), etc. In some cases, the canary stamp can be carried in an IOAMdata field as an IOAM Trace option data element (e.g., with an IOAMTrace type for node integrity canary stamp). A metadata element, token,or digest, e.g. canary stamp digest, can be added in the IOAM traceoption of a packet by each node that forwards the packet.

When the packet reaches a node (e.g., the destination node and/or anintermediate node) that removes IOAM metadata (e.g., an IOAMdecapsulating node), the validity of the metadata element and/or tokenin the packet can be verified to determine that the packet traverseduncompromised nodes. In some examples, since canary stamps are timebound, the packet trace timestamps defined in IOAM can be used tovalidate the canary stamp in the time window the packet traversed thatnode.

Verification can be performed without placing a large transactional loadon the verifier or a device, such as a controller, that will ultimatelyvalidate the security measurements associated with the metadata elementsor tokens. This is because the measurement values can often changeinfrequently. The verifier may only need to validate a metadata elementand/or token carried within an IOAM data trace whenever the associatedsecurity measurements associated change (e.g., a verifier may only needto check with a controller whenever it sees a node's TPM extend a PCRvalue which was not previously confirmed by the verifier).

In some cases, when only the time ticks within a signed metadata elementincreases, only the signature of the metadata element is validated. Todo this, the verifier may use the public key of any node which can placea metadata element. Such signature validation can be done without usinga controller to verify the measurements.

In another example, a packet can carry IOAM POT data with spaceoptimization of metadata element values, e.g. canary stamp values. Forexample, a new IOAM POT data field can carry a canary stamp or a hashextend of a canary stamp and, in turn, canary stamp data can be carriedacross nodes. In some cases, a canary stamp hash extend can be a similarmethod as PCR extend operation performed by TPMs.

In some cases, the canary stamp hash can provide a one-way hash so thata canary stamp recorded by any node cannot be removed or modifiedwithout detection. IOAM proof of transit option data for a canary stampdigest can be defined by a hash algorithm (e.g., 20 octets with SHA1, 32octets with SHA 256, etc.). In some implementations, each node along apath of the packet can forward the packet with a new or updated canarystamp digest. In some examples, the new or updated canary stamp digestcan be generated by a node as follows: IOAM canary stamp digest newvalue=Digest of (IOAM canary stamp digest old value 11 hash(canary stampof the node)), where the IOAM canary stamp digest old value can refer tothe canary stamp digest included in the packet by one or more previoushops.

Moreover, in some cases, a Per Packet Nonce (PPN), where PPN changes perpacket and is carried as another field within the IOAM metadata option,can be added to provide robustness against replay attacks. Toillustrate, in some examples, a PPN can be added as follows: IOAM canarystamp digest new value=Digest of (IOAM canary stamp digest old value ∥hash(canary stamp of the node ∥ PPN)). A node creating the new value forthe IOAM canary stamp digest can thus take the value of any previousIOAM canary stamp digest and extend/hash that value with the node'scurrent canary stamp. The result of the concatenation and hashing canthen be written into IOAM POT data (or other IOAM data fields) as thenew IOAM canary stamp digest.

At the verifier (e.g., the device verifying the canary stamp data), thesame operation can be performed over expected canary stamp valuescalculated for the nodes that are traversed in the time window when thepacket was forwarded. A verifier can be an inline device or acentralized device. Moreover, in some examples, nodes that are expectedto be traversed can be identified using IOAM tracing, routing state orby sending active probes. A match between the value of POT data carryingspecific metadata elements, e.g. a canary stamp digest and the expectedcanary stamp value, can prove that the packet traversed through trustedor uncompromised nodes.

In some examples, one or more strategies can be implemented to optimizemetadata element validation. For example, metadata elements, e.g. canarystamps, can detect attempts of a replay attack by embedding a nonce aswell as TPM or TPM2 counters (e.g., clock, reset, restart). In somecases, this nonce can be part of the metadata elements and differentfrom the PPN described above.

The nonce is relevant to a receiver as the interval from the nonce'screation time to the first stamp received by the verifier can define theinterval of freshness (e.g., the measurement is no older than thisinterval of freshness). From there, the TPM2 time ticks counter can beused to maintain that initial gap of freshness even without the deliveryof a new nonce.

In some implementations, to optimize metadata element or tokenvalidation across nodes, the following approaches can be implemented todeliver synchronization information from a central component to eachnode and the verifier. For example, a central server can broadcast ormulticast centralized nonce values (e.g., tracked random numbers). Eachnode can pick up the latest nonce and use it to attest a value. Averifier can know the freshness of a metadata element or token itreceives from each node. This freshness can be the delta in time sincethat particular nonce was issued. Subsequent attestations can use theincrementing time ticks to prove freshness from that initial time gap.In some cases, the issuing of new nonces can reset the time gap to apotentially shorter interval.

Moreover, in some cases, each node can embed attested time within itsmetadata element. To get attested time, a TUDA (Time-BasedUni-Directional Attestation) scheme such as the TUDA scheme described inhttps://tools.ietforg/id/draft-birkholz-i2nsf-tuda-01.html, the contentsof which are incorporated herein by reference in their entirety, can beused. This can result in the availability of both the attested time at anode, as well as the value of the TPM2 counters at this node when a TUDAtime-synchronization token was created. This can eliminate the use of acentral nonce authority, but can increase the size of the metadataelement as the nonce can be replaced by the TUDA time-synchronizationtoken. This approach may also implement a central timestamp authority asper TUDA. In some examples, for each hop, a canary stamp digest valuecan be: IOAM canary stamp digest new value=Digest of (IOAM canary stampdigest old value ∥ hash(canary stamp of the node ∥ TUDAtime-synchronization token of the node)).

This approach can provide numerous benefits. For example and withoutlimitation, with this approach, a verifier can limit the number ofverifications by verifying the signature of a hop's time-synchronizationtoken only when it changes. Moreover, with this approach, there may notbe a time gap nonce changeover freshness when a first measurement isreceived. Further, in some cases, this approach can be implementedwithout also carrying a PPN or without synchronizing a nonce acrossnodes as previously described.

Further, an attestor, e.g. a node or a verifier, can use random numbers,otherwise pseudo-random numbers, created by peers and/or the attestor togenerate and verify attestation information. Specifically, the attestorcan accumulate random numbers from one or more layer 2 peers. The randomnumbers can be accumulated from the peers over a specific amount oftime, e.g. a short duration of time. In turn, the random numbers can becombined into a number through an applicable technique, e.g. a Bloomfilter. This number can serve as a nonce for a cryptoprocessor forgenerating a result. As follows, the layer 2 peers, potentiallyincluding the attestor, can use the result created by thecryptoprocessor, to verify/validate that their corresponding providedrandom number was used in generating the nonce ultimately used by thecryptoprocessor to create the result. In turn, the layer 2 peers,potentially including the attestor, can generate verified attestationinformation based on the random numbers generated by the peers, thenonce created from the random numbers, and/or the result created by thecryptoprocessor from the nonce.

Having provided an initial discussion of example concepts andtechnologies for providing explicit verifiable proof of integrity ofnetwork nodes traversed by packets, the disclosure now turns to FIG. 1 .

FIG. 1 is a block diagram of an example of networking environment 100 inaccordance with some implementations. While pertinent features areshown, those of ordinary skill in the art will appreciate from thepresent disclosure that various other features have not been illustratedfor the sake of brevity and so as not to obscure aspects of the exampleimplementations disclosed herein.

In this example, the networking environment 100 can include a network114 of interconnected nodes (e.g., 108A-N, 110A-N, and 112A-N). Thenetwork 114 can include a private network, such as a local area network(LAN), and/or a public network, such as a cloud network, a core network,and the like. In some implementations, the network 114 can also includeone or more sub-networks, such as sub-network 114A. Sub-network 114A caninclude, for example and without limitation, a LAN, a virtual local areanetwork (VLAN), a datacenter, a cloud network, a wide area network(WAN), etc. In some examples, the sub-network 114A can include a WAN,such as the Internet. In other examples, the sub-network 114A caninclude a combination of nodes included within a LAN, VLAN, and/or WAN.

The networking environment 100 can include a source node 102. The sourcenode 102 can be a networking device (e.g., switch, router, gateway,endpoint, etc.) associated with a data packet that is destined for adestination node 116. The source node 102 can communicate with candidatenext-hop nodes 108A-N on the network 114. Each of the candidate next-hopnodes 108A-N can be included within a respective route between thesource node 102 and the destination node 116. Moreover, in some cases,each of the candidate next-hop nodes 108A-N can communicate withcandidate second hop nodes 110A-N in the network 114. Each of thecandidate second hop nodes 110A-N can similarly communicate withcandidate N-hop nodes 112A-N in the network 114.

The networking environment 100 can also include an attestation routingorchestrator 104. The attestation routing orchestrator 104 cancommunicate with the candidate next-hop nodes 108A-N. In someimplementations, the attestation routing orchestrator 104 can obtainattestation data (e.g., canary stamps, security measures, signatures,and/or metadata) or vectors from the candidate next-hop nodes 108A-N. Insome examples, the attestation routing orchestrator 104 can obtainadditional information from candidate second-hop nodes 110A-N and/orcandidate N-hop nodes 112A-N and utilize the additional information inselecting a particular candidate next-hop node for a packet. In someimplementations, the attestation routing orchestrator 104 can alsoobtain additional information from nodes that are more than two hopsaway (e.g., candidate third hop nodes, candidate fourth hop nodes,etc.).

The attestation routing orchestrator 104 can communicate with a verifiersystem 106. While, the verifier system 106 is conceptually shown asbeing implemented separate from the network 114, the verifier system 106can be implemented within the network 114, e.g. as part of a networkdevice in the network 114. In some implementations, the attestationrouting orchestrator 104 can obtain trusted state, such as a trustedimage vector, from the verifier system 106. The verifier system 106 caninclude a verified state repository 106A and one or more servers 106B.In some examples, the verified state in the verified state repository106A can include one or more verified images, verified securitymeasurements, verified settings, verified node data, and/or any otherverified trust or integrity data. In some implementations, the verifiedstate in the verified state repository 106A can include one or moretrusted states or image vectors that are known with a degree ofconfidence to represent uncompromised states or images (e.g., states orimages that have not been hacked, attacked, improperly accessed, etc.).

As will be described in great detail with reference to FIG. 4 , in somecases, the attestation routing orchestrator 104 can select and direct adata packet to a particular candidate next-hop node of the candidatenext-hop nodes 108A-N based on a trusted state or image vector and theattestation states or vectors. Moreover, the attestation routingorchestrator 104 can direct the data packet destined for the destinationnode 116 to the particular candidate next-hop node.

FIG. 2 is a block diagram of another example networking environment 200in accordance with some implementations. In this example, the networkingenvironment 200 includes a source node 202 that implements anattestation routing orchestrator 202A. In some implementations, theattestation routing orchestrator 202A can be similar to, or adaptedfrom, the attestation routing orchestrator 104 in FIG. 1 .

The source node 202 can include one or more processors 202B. In someimplementations, the one or more processors 202B can provide processingresources for generating a confidence scores for the candidate next-hopnodes 108A-N. In some implementations, the one or more processors 202Bcan provide processing resources for selecting a particular confidencescore, from the confidence scores, that satisfies one or more selectioncriteria.

In some examples, the source node 202 can include a memory 202C. Thememory 202C can be, for example and without limitation, a non-transitorymemory, such as RAM (random-access memory), ROM (Read-only memory), etc.The memory 202C can store the data, such as the packet destined for thedestination node 116. In some implementations, the memory 202C can storea trusted state or image vector obtained from the verifier system 106.In some implementations, the memory 202C can store attestation states orvectors obtained from the candidate next-hop nodes 108A-N and optionallyattestation states or vectors obtained from the candidate second hopnodes 110A-N and/or the candidate N-hop nodes 112A-N. The source node202 can also include a network interface 202D for obtaining, receiving,and transmitting the data packets and states or vectors.

In some implementations, the source node 202 can select and direct adata packet to a particular candidate next-hop node based a trustedstate or image vector and the attestation states or vectors.

FIG. 3 is a block diagram of another example networking environment 300in accordance with some implementations. In this example, one or more ofthe candidate next-hop nodes 108A-N can relay a trusted state or imagevector from the verifier system 106 to the source node 302. In someimplementations, the attestation routing orchestrator 302A can besimilar to, or adapted from, the attestation routing orchestrator 104 inFIG. 1 and/or the attestation routing orchestrator 202A in FIG. 2 .

In some implementations, the verifier system 106 can sign the trustedstate or image vector and provide the signed trusted state or imagevector to a particular candidate next hop node, which in turn canprovide the signed trusted state or image vector to the source node 302.In some implementations, having the particular candidate next hop nodeprovide the signed trusted state or image vector can reduce attestationtime (e.g., the time to determine trustworthiness of the particularcandidate next hop node) because the source node 302 may not need tocontact a remote node (verifier system 106). In some implementations,attestation time can be further reduced because a single attestationprocess (e.g., the verifier system 106 signing the trusted state orimage vector) facilitates the attesting of multiple source nodes. Inother words, trusted states or image vectors may not be generated andevaluated on a per source node basis.

Moreover, in implementations in which the source node 302 is notconnected to the verifier system 106 (e.g., link down), obtaining thetrusted state or image vector from the particular candidate next hopprovides an alternative mechanism for node attestation. In someimplementations, the verifier system 106 appends a time-stamped responseto the trusted state or image vector as part of the signing process,which can be referred to as stapling. Consequently, the source node 302may not contact the verifier system 106 in order to attest a particularcandidate next hop node.

FIG. 4 is a block diagram of an example controller-orchestratedattestation-based routing 400, in accordance with some implementations.In some examples, the source node 402 is similar to, or adapted from,the source node 102 in FIG. 1 . As illustrated in FIG. 4 , theattestation routing orchestrator 104 is separate from, but coupled(e.g., connected) to, the source node 402. In some examples, theattestation routing orchestrator 104 can include a controller withknowledge of the network 114 that includes the candidate next-hop nodes108A-N and optionally the candidate second-hop nodes 110A-N and/or thecandidate N-hop nodes 112A-N.

For example, in some implementations, the attestation routingorchestrator 104 can be a network management system (NMS). As anotherexample, in some implementations, the attestation routing orchestrator104 can be an intent-based networking system, such as Cisco's DigitalNetwork Architecture (DNA). As yet another example, in someimplementations, the attestation routing orchestrator 104 can be awireless LAN controller (WLC), and the candidate next-hop nodes 108A-Nand optionally the candidate second hop nodes 110A-N and/or thecandidate N-hop nodes 112A-N can be networking devices such as accesspoints, user devices, switches, routers, firewalls, etc.

The attestation routing orchestrator 104 can obtain attestation data(e.g., canary stamps) from the candidate next-hop nodes 108A-N. Each ofthe candidate next-hop nodes 108A-N can be included within a respectiveroute between the source node 402 and a destination node (e.g., 114). Insome implementations, the respective routes are independent of eachother.

The attestation routing orchestrator 104 can determine confidence scoresbased on the attestation data. For example, in some cases, each of theconfidence scores can be based on a comparison between a correspondingone of the attestation data and a trusted state or image vector. In someimplementations, the attestation routing orchestrator 104 can obtain thetrusted state or image vector from the verifier system 106.

In some examples, the attestation routing orchestrator 104 can obtainattestation data from candidate second-hop nodes (e.g., 110A-N) and/orcandidate N-hop nodes (112A-N). Each of the candidate second-hop nodesand/or the candidate N-hop nodes can be included within a respectiveroute between a corresponding one of the candidate next-hop nodes 108A-Nand the destination node. Moreover, each of the confidence scores canadditionally be based on a comparison between a corresponding one of theattention data and the trusted state or image vector in combination witha comparison between another corresponding one of the attestation datafrom the candidate next-hop nodes 108A-N and the trusted state or imagevector.

The attestation routing orchestrator 104 can select, from the confidencescores, a particular confidence score that satisfies one or moreselection criteria. The particular confidence score is associated with aparticular candidate next-hop node of the candidate next-hop nodes108A-N.

The attestation routing orchestrator 104 can directs, to the particularcandidate next-hop node, a data packet destined for the destinationnode. For example, in some cases, the attestation routing orchestrator104 can provide attested route information (e.g., validated canary stampdata, security measurements, etc.) to an attested route manager 402D ofthe source node 402 in order to facilitate the source node 402 sendingthe data packet to the particular candidate next-hop node. The attestedroute information can be indicative of the trustworthiness of each ofthe candidate next-hop nodes 108A-N.

For example, in some implementations, the attested route informationincludes an identifier (e.g., an IP address, a MAC address, an SSID,etc.) identifying a secure candidate next-hop node of the candidatenext-hop nodes 108A-N. In this example, the source node 402 can providethe data packet based on the identifier in order to route the datapacket to the secure, particular candidate next-hop node.

As another example, in some implementations, the attested routeinformation can include confidence scores associated with the candidatenext-hop nodes 108A-N. In this example, the attested route manager 402Dcan select a particular candidate score based on one or more selectioncriteria. Moreover, the attested route manager 402D can provide the datapacket to the particular next-hop node associated with the particularcandidate score. In some examples, the attestation routing orchestrator104 can cease to direct additional data packets to the particularcandidate next-hop node in response to determining that the particularconfidence score falls below a confidence threshold.

In some cases, the source node 402 can include one or more processors402A. The one or more processors 402A can provide processing resourcesfor managing attested route information obtained from the attestationrouting orchestrator 104. The source node 402 can also include a memory402B. The memory 402B can include, for example, a non-transitory memorysuch as RAM, ROM, etc. In some examples, the memory 402B can store datasuch as the obtained attested route information and data packets to betransmitted. The source node 402 can also include a network interface402C for obtaining the attested route information and sending/receivingother data.

In some cases, whether a network device has been compromised can bedetermined based on indicators associated with the network device andtime information. The indicators can include, but are not limited to, aset of security measurements or evidence footprints which indicatewhether a particular device is compromised. Such indicators can comefrom one or more sources such as, for example and without limitation,TPM, canary stamps, Syslog, YANG Push, EEM, peer devices, trafficcounters, and other sources. Visibility can be a method of identifying acompromise in a timely manner.

The disclosure now turns to FIGS. 5 and 6 , which illustrate an examplesystem and method for implementing some aspects of the presenttechnology.

Modular devices or devices with multiple hardware roots of trust poseparticular challenges for security assessment. The presence of multiplehardware roots of trust means that all must be verified independently toensure that no portion of the overall device has been compromised.Modular devices pose an even greater challenge, where portions of thedevice may be replaced but security assessments must last the lifetimeof the deployed device.

The present technology solves a need in the art for secure verificationof modular devices with multiple hardware roots of trust across thelifetime of the device. Using double-signed security measurements alongwith an enrollment key spanning the lifetime of the logical device (asopposed to the physical device), FIGS. 5 and 6 detail a system andmethod, respectively, for this technology.

FIG. 5 illustrates an example system in accordance with some aspects ofthe present technology. A network device with a trusted processor modulecontains modules with their own trusted processor modules. The modulescan be verified by the network device, which in turn saves a dossier ofvalidation information in a secure enclave. External sources, such asother network devices or services (e.g., verifier system 106 describedabove with reference to FIGS. 1-4 ), can verify the integrity of thenetwork device using the dossier stored in the secure enclave.

Network device 500 contains a trusted processor module 530, a secureenclave 540, and modules 510, 511, and 512 with their own trustedprocessor modules 520, 521, and 522, respectively. Network device 500can be a router, border gateway, edge node, or any other device on amanaged network. In some embodiments, modules 510, 511, and 512 can bereplaced over the lifetime of network device 500; in others, the modulesare built-in to network device 500 and are not replaceable.

Modules 510, 511, and 512 exist in network device 500 with their owntrusted processor modules 520, 521, and 522, respectively. These trustedprocessor modules 520, 521, and 522 represent hardware roots of trustfor modules 510, 511, and 512, as discussed above. In some embodiments,modules 510, 511, and 512 can be line cards or route processors toreceive, transmit, or control network flows.

Trusted processor module 530 is the hardware root of trust for networkdevice 500. Unlike trusted processor modules 520, 521, and 522, it isnot embedded in a module but exists in network device 500. Secureenclave 540 prevents exfiltration of stored data from networking device500. Secure enclave 540 can securely replicate stored data to a backupentity, such as a backup module 510, within networking device 500.

Trusted processor module 530 can request a security measurement from atrusted processor module 520 on a module 510. A security measurementassesses the status of module 510, determining whether or not it hasbeen compromised. A security measurement can include integritymeasurements from trusted processor module 520, among other data. Therequest can include a nonce plus signed timeticks, and reset and restartcounters. These elements of the request can insure that securitymeasurements are not replayed or reused from a different request.

Trusted processor module 530 can receive signed, stamped securitymeasurements from each of modules 510, 511, and 512. Trusted processormodule 530 can verify and sign each of the received securitymeasurements if it agrees that the signature keys of modules 510, 511,and 512 are valid, and modules 510, 511, and 512 can store public keysfor this purpose in trusted processor module 530. The verified securitymeasurements are compiled into a dossier by trusted processor module530, which then signs the dossier. The dossier represents the state ofnetworking device 500, and includes security measurements and signaturesfrom all hardware roots of trust on device 500.

The dossier can be signed by an enrollment key stored in trustedprocessor module 530. This enrollment key identifies the logical device500 instead of the physical device 500. This allows the enrollment keyto persist for the duration of the lifecycle of networking device 500,independent of replacement parts or new modules 510, 511, or 512. Theenrollment key is enrolled in a service 550 that will report on trustevidence for networking device 500 by a remote attestation process.

In some embodiments, the key enrollment comprises an asymmetric cipherwith a private key component stored in secure enclave 540 used to sign acertificate chain issued by a certificate authority and a correspondingx.509 certificate which is either a self-signed certificate authority orroot certificate signed by a customer's root certificate authority.Individual signing keys can be created by the self-signed root and areused to control key entropy over time without requiring a re-enrollmentof a new signing key with the service.

Secure enclave 540 can securely store and replicate the signed dossierreceived from trusted processor module 530. When an external service 550wants to verify the integrity of network device 500, it can request thedossier from secure enclave 540, which can return verificationinformation to service 550 signed by the enrollment key.

FIG. 6 illustrates an example method in accordance with some aspects ofthe present technology.

At process 600, supervisor trusted processor module 530 sends a requestfor a signed security measurement to a module 510. This request cancontain a nonce plus signed timeticks, and reset and restart counters.These elements of the request can insure that security measurements arenot replayed or reused from a different request.

At process 605, the module 510 receives the request for the signedsecurity measurement. In response, at process 610, module 510 generatesthe signed security measurement by trusted processor module 520. Thesigned security measurement can include integrity measurements or othersecurity information pursuant to module 510. At process 615, module 510sends the signed security measurement to trusted processor module 530,and trusted processor module 530 receives the signed securitymeasurement at process 620.

At process 625, supervisor trusted processor module 530 validates thesigned security measurement received from module 510. Trusted processormodule 530 can validate the signed security measurement by comparing thesignature keys of module 510 with public keys for this purpose intrusted processor module 530.

After process 625, the method can return to process 600 with a separatemodule 511. Processes 600 through 625 need to occur at least once tocover at least one module 510. At process 627, supervisor trustedprocessor module 530 determines if all modules in device 500 have beencovered. If not (No at process 627), the process reverts back to process600 and processes 600 to 627, as described above, are repeated until allmodules are covered. Once all modules are covered (Yes at process 627),the method proceeds to process 630 accordingly.

At process 630, supervisor trusted processor module 530 signs allreceived and verified signed security measurements compiled in adossier. This dossier is signed by an enrollment key stored in trustedprocessor module 530. This enrollment key identifies the logical device500 instead of the physical device 500, which allows the enrollment keyto persist for the duration of the lifecycle of networking device 500,independent of replacement parts or new modules 510. The enrollment keyis enrolled in a service 550 that will report on trust evidence fornetworking device 500 by a remote attestation process.

At this point, each set of security measurements has been signed twice(double signed). First, it is signed by the trusted processor module onthe module the security measurements are for. Then, after verificationby supervisor trusted processor module 530, it is signed by supervisortrusted processor module 530 on the dossier.

At process 635, trusted processor module 530 sends the signed dossier tosecure enclave 540, which receives the signed dossier at process 640. Atprocess 645, secure enclave 540 securely stores the signed dossier forlater device validation and replication. A remote service such asservice 550 (e.g., verifier 106 of FIGS. 1-4 ) can then use this dossierto ensure the security of device 500. Remote attestation of the device500 as a whole, or of an individual module 510, is then possible.

The disclosure now turns to FIGS. 7 and 8 , which illustrate examplenetwork nodes and computing devices, such as switches, routers, clientdevices, endpoints, servers, and so forth.

FIG. 7 illustrates an example network device 700 suitable for performingswitching, routing, and other networking operations. Network device 700includes a central processing unit (CPU) 704, interfaces 702, and aconnection 710 (e.g., a PCI bus). When acting under the control ofappropriate software or firmware, the CPU 704 is responsible forexecuting packet management, error detection, and/or routing functions.The CPU 704 can accomplish these functions under the control of softwareincluding an operating system and any appropriate applications software.CPU 704 may include one or more processors 708, such as a processor fromthe INTEL X86 family of microprocessors. In some cases, processor 708can be specially designed hardware for controlling the operations ofnetwork device 700. In some cases, a memory 706 (e.g., non-volatile RAM,ROM, etc.) also forms part of CPU 704. However, there are many differentways in which memory could be coupled to the system.

The interfaces 702 are typically provided as modular interface cards(sometimes referred to as “line cards”). Generally, they control thesending and receiving of data packets over the network and sometimessupport other peripherals used with the network device 700. Among theinterfaces that may be provided are Ethernet interfaces, frame relayinterfaces, cable interfaces, DSL interfaces, token ring interfaces, andthe like. In addition, various very high-speed interfaces may beprovided such as fast token ring interfaces, wireless interfaces,Ethernet interfaces, Gigabit Ethernet interfaces, ATM interfaces, HSSIinterfaces, POS interfaces, FDDI interfaces, WIFI interfaces, 3G/4G/5Gcellular interfaces, CAN BUS, LoRA, and the like. Generally, theseinterfaces may include ports appropriate for communication with theappropriate media. In some cases, they may also include an independentprocessor and, in some instances, volatile RAM. The independentprocessors may control such communications intensive tasks as packetswitching, media control, signal processing, crypto processing, andmanagement. By providing separate processors for the communicationsintensive tasks, these interfaces allow the master microprocessor 704 toefficiently perform routing computations, network diagnostics, securityfunctions, etc.

Although the system shown in FIG. 7 is one specific network device ofthe present technologies, it is by no means the only network devicearchitecture on which the present technologies can be implemented. Forexample, an architecture having a single processor that handlescommunications as well as routing computations, etc., is often used.Further, other types of interfaces and media could also be used with thenetwork device 700.

Regardless of the network device's configuration, it may employ one ormore memories or memory modules (including memory 706) configured tostore program instructions for the general-purpose network operationsand mechanisms for roaming, route optimization and routing functionsdescribed herein. The program instructions may control the operation ofan operating system and/or one or more applications, for example. Thememory or memories may also be configured to store tables such asmobility binding, registration, and association tables, etc. Memory 706could also hold various software containers and virtualized executionenvironments and data.

The network device 700 can also include an application-specificintegrated circuit (ASIC) 712, which can be configured to performrouting and/or switching operations. The ASIC 712 can communicate withother components in the network device 700 via the connection 710, toexchange data and signals and coordinate various types of operations bythe network device 700, such as routing, switching, and/or data storageoperations, for example.

FIG. 8 illustrates a computing system architecture 800 including variouscomponents in electrical communication with each other using aconnection 806, such as a bus. Example system architecture 800 includesa processing unit (CPU or processor) 804 and a system connection 806that couples various system components including the system memory 820,such as read only memory (ROM) 818 and random access memory (RAM) 816,to the processor 804. The system architecture 800 can include a cache802 of high-speed memory connected directly with, in close proximity to,or integrated as part of the processor 804. The system architecture 800can copy data from the memory 820 and/or the storage device 808 to thecache 802 for quick access by the processor 804. In this way, the cachecan provide a performance boost that avoids processor 804 delays whilewaiting for data. These and other modules can control or be configuredto control the processor 804 to perform various actions.

Other system memory 820 may be available for use as well. The memory 820can include multiple different types of memory with differentperformance characteristics. The processor 804 can include any generalpurpose processor and a hardware or software service, such as service 1810, service 2 812, and service 3 814 stored in storage device 808,configured to control the processor 804 as well as a special-purposeprocessor where software instructions are incorporated into the actualprocessor design. The processor 804 may be a completely self-containedcomputing system, containing multiple cores or processors, a bus, memorycontroller, cache, etc. A multi-core processor may be symmetric orasymmetric.

To enable user interaction with the computing system architecture 800,an input device 822 can represent any number of input mechanisms, suchas a microphone for speech, a touch-sensitive screen for gesture orgraphical input, keyboard, mouse, motion input, speech and so forth. Anoutput device 824 can also be one or more of a number of outputmechanisms known to those of skill in the art. In some instances,multimodal systems can enable a user to provide multiple types of inputto communicate with the computing system architecture 800. Thecommunications interface 826 can generally govern and manage the userinput and system output. There is no restriction on operating on anyparticular hardware arrangement and therefore the basic features heremay easily be substituted for improved hardware or firmware arrangementsas they are developed.

Storage device 808 is a non-volatile memory and can be a hard disk orother types of computer readable media which can store data that areaccessible by a computer, such as magnetic cassettes, flash memorycards, solid state memory devices, digital versatile disks, cartridges,random access memories (RAMs) 816, read only memory (ROM) 818, andhybrids thereof.

The storage device 808 can include services 810, 812, 814 forcontrolling the processor 804. Other hardware or software modules arecontemplated. The storage device 808 can be connected to the systemconnection 806. In one aspect, a hardware module that performs aparticular function can include the software component stored in acomputer-readable medium in connection with the necessary hardwarecomponents, such as the processor 804, connection 806, output device824, and so forth, to carry out the function.

For clarity of explanation, in some instances the present technology maybe presented as including individual functional blocks includingfunctional blocks comprising devices, device components, steps orroutines in a method embodied in software, or combinations of hardwareand software.

In some embodiments the computer-readable storage devices, mediums, andmemories can include a cable or wireless signal containing a bit streamand the like. However, when mentioned, non-transitory computer-readablestorage media expressly exclude media such as energy, carrier signals,electromagnetic waves, and signals per se.

Methods according to the above-described examples can be implementedusing computer-executable instructions that are stored or otherwiseavailable from computer readable media. Such instructions can comprise,for example, instructions and data which cause or otherwise configure ageneral purpose computer, special purpose computer, or special purposeprocessing device to perform a certain function or group of functions.Portions of computer resources used can be accessible over a network.The computer executable instructions may be, for example, binaries,intermediate format instructions such as assembly language, firmware, orsource code. Examples of computer-readable media that may be used tostore instructions, information used, and/or information created duringmethods according to described examples include magnetic or opticaldisks, flash memory, USB devices provided with non-volatile memory,networked storage devices, and so on.

Devices implementing methods according to these disclosures can comprisehardware, firmware and/or software, and can take any of a variety ofform factors. Typical examples of such form factors include laptops,smart phones, small form factor personal computers, personal digitalassistants, rackmount devices, standalone devices, and so on.Functionality described herein also can be embodied in peripherals oradd-in cards. Such functionality can also be implemented on a circuitboard among different chips or different processes executing in a singledevice, by way of further example.

The instructions, media for conveying such instructions, computingresources for executing them, and other structures for supporting suchcomputing resources are means for providing the functions described inthese disclosures.

Although a variety of examples and other information was used to explainaspects within the scope of the appended claims, no limitation of theclaims should be implied based on particular features or arrangements insuch examples, as one of ordinary skill would be able to use theseexamples to derive a wide variety of implementations. Further andalthough some subject matter may have been described in languagespecific to examples of structural features and/or method steps, it isto be understood that the subject matter defined in the appended claimsis not necessarily limited to these described features or acts. Forexample, such functionality can be distributed differently or performedin components other than those identified herein. Rather, the describedfeatures and steps are disclosed as examples of components of systemsand methods within the scope of the appended claims.

Claim language reciting “at least one of” a set indicates that onemember of the set or multiple members of the set satisfy the claim. Forexample, claim language reciting “at least one of A and B” means A, B,or A and B.

The invention claimed is:
 1. A method comprising: requesting at leastone signed security measurement from at least one module, the at leastone module existing within a physical device; receiving the at least onesigned security measurement from the at least one module; validating theat least one signed security measurement; and generating a signeddossier including all validated signed security measurements in a secureenclave, the signed dossier being used by an external network device forremote attestation of the physical device; wherein the generating thesigned dossier includes signing the dossier with a key which representsa virtual device representation of the physical device and is not tiedto a specific hardware component associated with the physical device. 2.The method of claim 1, wherein the at least one signed securitymeasurement contains integrity measurements from a cryptoprocessor ofthe at least one module.
 3. The method of claim 1, wherein therequesting the at least one signed security measurement includes sendinga nonce plus signed timeticks, as well as reset and restart counters. 4.The method of claim 1, wherein the at least one module is a line card ora route processor.
 5. The method of claim 1, wherein the key comprisesan asymmetric cipher.
 6. The method of claim 5, wherein the asymmetriccipher has a private key component stored in the secure enclave used forgenerating the signed dossier.
 7. The method of claim 1, wherein thesigned dossier is securely distributed between multiple secure enclaves.8. A non-transitory computer-readable storage medium comprisinginstructions stored therein which, when executed by at least oneprocessor, cause the at least one processor to: request a plurality ofsigned security measurements from a plurality of modules, the pluralityof modules existing within a physical device; receive the plurality ofsigned security measurements from the plurality of modules; validate theplurality of signed security measurement; and generate a signed dossierincluding all validated signed security measurements in a secureenclave, the signed dossier being used by an external network device forremote attestation of the physical device; wherein the generate thesigned dossier includes signing the dossier with a key which representsa virtual device representation of the physical device and is not tiedto a specific hardware component associated with the physical device. 9.The non-transitory computer-readable storage medium of claim 8, whereinthe plurality of modules contain at least one line card or a routeprocessor.
 10. The non-transitory computer-readable storage medium ofclaim 8, wherein the plurality of signed security measurements containintegrity measurements from a cryptoprocessor of the at least onemodule.
 11. The non-transitory computer-readable storage medium of claim8, wherein the request of the plurality of signed security measurementsincludes sending a nonce plus signed timeticks, as well as reset andrestart counters.
 12. The non-transitory computer-readable storagemedium of claim 8, wherein the key comprises an asymmetric cipher. 13.The non-transitory computer-readable storage medium of claim 12, whereinthe asymmetric cipher has a private key component stored in the secureenclave used for generating the signed dossier.
 14. The non-transitorycomputer-readable storage medium of claim 8, wherein the signed dossieris securely distributed between multiple secure enclaves.
 15. A systemcomprising: at least one processor; a non-transitory computer-readablestorage medium comprising instructions stored therein which, whenexecuted by at least one processor, cause the system to: request aplurality of signed security measurements from a plurality of modules,the plurality of modules existing within a physical device; receive theplurality of signed security measurements from the plurality of modules;validate the plurality of signed security measurement; and generate asigned dossier including all validated signed security measurements in asecure enclave, the signed dossier being used by an external networkdevice for remote attestation of the physical device; wherein thegenerate the signed dossier includes signing the dossier with a keywhich represents a virtual device representation of the physical deviceand is not tied to a specific hardware component associated with thephysical device.
 16. The system of claim 15, wherein the at least onemodule is a line card or a route processor.
 17. The system of claim 15,wherein the at least one signed security measurement contains integritymeasurements from a cryptoprocessor of the at least one module.
 18. Thesystem of claim 15, wherein the request of the at least one signedsecurity measurement includes a nonce plus signed timeticks, as well asreset and restart counters.
 19. The system of claim 15, wherein the keycomprises an asymmetric cipher with a private key component stored inthe secure enclave used for generating the signed dossier.
 20. Thesystem of claim 15, wherein the signed dossier is securely distributedbetween multiple secure enclaves.